The present invention relates to a nozzle restrictor assembly for a fuel filler tube of a vehicle or the like and a method for installing a nozzle restrictor assembly in a fuel filler tube. More particularly, the present invention relates to a restrictor assembly designed to simplify the manufacturing process for fuel filler tubes, particularly with respect to protective coating operations.
Vehicle fuel filler tubes typically include nozzle restrictor assemblies at or near the inlet end thereof. The restrictor assemblies are designed to prevent passage of large diameter fuel filler nozzles into the fuel filler tube. Many consumers accustomed to pumping gasoline at a self service filling station have noticed that large diameter nozzles are always provided on pumps that dispense leaded fuel while small diameter nozzles are always provided on pumps that dispense unleaded fuel.
A restrictor assembly is designed so that fuel filler nozzles dispensing leaded fuel have a nozzle diameter too large to pass through the nozzle-receiving aperture that is formed in the restrictor assembly, thus compelling a user to switch to a small diameter nozzle on an unleaded fuel pump and follow requirements to use unleaded fuel. Such a restrictor assembly typically includes a threaded cup mounted in the filler neck and formed to include a small diameter opening for receiving the small diameter fuel filler nozzle and a spring deflector for normally covering the opening.
In current manufacturing processes for fuel filler tubes, the filler tube is coated with a protective coating prior to the installation of the restrictor assembly. The various components of the restrictor assembly must be assembled off-line and coated separately from the fuel filler tube. The pre-coated restrictor assembly is then pressed into the pre-coated fuel filler tube.
Generally, the fuel cap, when installed on the fuel filler tube, provides a barrier to fuel vapor leakage. However, for restrictor assemblies using a threaded cup, the fuel cap is threaded into the threaded cup and does not seal the joint between the threaded cup and the inner wall of the fuel filler tube. Accordingly, the joint between the restrictor assembly and the filler neck must be carefully sealed during an extra sealing operation to prevent leakage of fuel vapor through the joint between the pre-coated restrictor assembly and the inner wall of the pre-coated fuel filler tube.
The type of extra sealing operation employed to seal conventional restrictor assemblies is dependent upon the type of protective coating which has been applied to the restrictor assembly and the fuel filler tube. Where the protective coating is a lead/tin dip coating or the like, sealing is accomplished by soldering the restrictor assembly to the fuel filler tube. Where the protective coating is paint, sealing is accomplished by the use of O-rings or adhesives. In either case, minor imperfections in the sealing medium or its method of application can cause unacceptable fuel vapor leakage through the joint between the conventional restrictor assembly and the fuel filler tube.
According to the present invention, a method is provided for installing a restrictor assembly in a fuel filler tube. The method comprises the steps of providing a restrictor plate formed to include an opening allowing passage of a fuel filler nozzle therethrough and a slot, attaching the restrictor plate to an inner wall of the fuel filler tube, coating the restrictor plate and the fuel filler tube, and inserting a closure plate through the slot to block the opening and provide a restrictor assembly inside the fuel filler tube.
Preferably, the coating step is performed before the inserting step. Using this method, the fuel filler tube and the restrictor plate are coated in a single step to seal any joint between the tube and plate after the restrictor plate has been attached to the inner wall of the fuel filler tube. Advantageously, all moving parts of the restrictor assembly (such as the closure plate) are mounted on the restrictor plate after the restrictor plate and the fuel filler tube have been properly coated.
In preferred embodiments, one portion of the closure member is inserted through the slot formed in the restrictor plate and another portion of the closure plate is pivoted to lock into place in engagement with the restrictor plate. Once properly assembled, the closure plate bears against a side of the restrictor plate facing away from the user and toward the vehicle fuel tank to cover the nozzle-receiving opening.
The present invention also provides an apparatus facilitating simplified and efficient assembly as heretofore described. The nozzle restrictor assembly of the present invention includes a restrictor plate formed to include an opening allowing passage of a fuel filler nozzle therethrough and means for selectively closing the opening upon withdrawal of the fuel filler nozzle. The restrictor plate is formed to include a slot and the closing means is sized for insertion through the slot.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived by the inventor.